Flowise affected by Server-Side Request Forgery (SSRF) in HTTP Node Leading to Internal Network Access
Description:
Flowise exposes an HTTP Node in AgentFlow and Chatflow that performs server-side HTTP requests using user-controlled URLs. By default, there are no restrictions on target hosts, including private/internal IP ranges (RFC 1918), localhost, or cloud metadata endpoints.
This enables Server-Side Request Forgery (SSRF), allowing any user interacting with a publicly exposed chatflow to force the Flowise server to make requests to internal network resources that are inaccessible from the public internet.
Impact includes:
- Access to internal admin panels (e.g., internal company dashboards, Jenkins, Kubernetes API, etc.).
- Retrieval of cloud provider metadata (e.g., AWS IMDSv1 at [http://169.254.169.254], GCP, Azure).
- Port scanning and enumeration of internal services.
- Potential lateral movement or privilege escalation in compromised environments.
This vulnerability is particularly severe because:
- Flowise instances are often deployed publicly without authentication (FLOWISE_USERNAME/PASSWORD not set by default).
- The HTTP Node is easily accessible in simple flows with minimal configuration.
Proof of Concept (PoC):
A minimal flow consisting of three nodes demonstrates successful internal network access:
Flow Structure:
<img width="1131" height="323" alt="image" src="https://github.com/user-attachments/assets/f6ddc74f-3ae9-4376-995a-693fb272627a" />
HTTP Node Configuration:
The HTTP Node is configured to perform a GET request to an internal address on localhost:
URL: http://127.0.0.1:8000 (or any internal service)
<img width="568" height="759" alt="image" src="https://github.com/user-attachments/assets/a5735e1f-f735-4d01-9d72-a772963254c8" />
Successful Response from Internal Service:
When the flow is triggered via chat input, the Flowise server successfully retrieves and returns content from the internal mock server running on port 8000 within the same container/network:
<img width="377" height="627" alt="image" src="https://github.com/user-attachments/assets/ff3fcfc6-4957-4aae-9c9d-13b4fca1d0ef" />
Impact
This is a Server-Side Request Forgery (SSRF) vulnerability with both read and write capabilities.
The HTTP Request node supports all standard HTTP methods (GET, POST, PUT, PATCH, DELETE), allowing attackers to not only retrieve sensitive information but also modify, create, or delete data on internal services if those services expose mutable endpoints:
- Read access: Retrieval of sensitive internal data, cloud provider metadata (e.g., AWS IAM credentials at http://169.254.169.254/latest/meta-data/iam/security-credentials/), secrets, configuration files, or database contents.
- Write access: Modification or deletion of internal resources via POST/PUT/PATCH/DELETE methods (e.g., creating malicious users/configurations, overwriting files, deleting data, triggering destructive actions on internal admin panels, CI/CD systems like Jenkins, Kubernetes APIs, or cloud management interfaces).
Amplification: Retrieved cloud credentials can be used for further privilege escalation or lateral movement outside the n8n instance.
Suggested Long-term Fix (for Flowise):
- Add optional security controls to HTTP Node:
- Toggle: "Block private IP ranges and localhost" (enabled by default).
- Field: "Allowed domains" (whitelist).
- Display prominent warning when URL field uses template variables (e.g., {{ }}).
- Update documentation with explicit SSRF risks and best practices.
Latest trending attack
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Google Brotli decoder - Remote Code Execution via compressed requests (Exploitation Check)
This control is the second step of the Patrowl response to CVE-2026-111497 (Node2Shell). It complements the first control of 22 October 2026, which focused on the Node.js runtime, and does not replace it.
Why a second control
CVE-2026-111497 is an out-of-bounds write in the Google Brotli decoder, the library that decompresses Brotli ("br") data. It was first published as a Node.js vulnerability, because Node.js bundles this decoder. Later publications showed that the flaw is in the library itself. Every product that embeds an affected version of the decoder is concerned, whatever its language or vendor. A public proof of concept demonstrates code execution.
Any server that decompresses request bodies sent with "Content-Encoding: br" exposes the decoder to unauthenticated attackers. Known cases include Express 5 and NestJS 11 on Node.js, Koa and Fastify setups, Bun, Envoy and Istio with request decompression enabled, and any application or reverse proxy that decodes Brotli request bodies with an affected library.
The flaw also works in the other direction. A malicious server can compromise an unpatched client that decodes a Brotli response, for example Node.js fetch(), Python clients (requests, httpx, aiohttp, Scrapy) with the Brotli or brotlicffi package, or libcurl builds with Brotli support.
What this control checks
Patrowl sends small, valid Brotli-compressed requests to each asset and observes whether the server decodes them. The check does not depend on the technology: it detects the behaviour, whatever the stack behind it. These requests are what any legitimate client could send. They never reach the vulnerable code path and cannot affect the availability of the service.
How to read the result
Potentially impacted means the asset decodes Brotli request bodies: the attack surface is exposed. It does not confirm that the asset is vulnerable. The version of the Brotli decoder in use is not visible from the outside.
This check covers applications that parse request bodies on their root path. A Not impacted result does not rule out exposure on other routes, nor on the client side. Checking the versions on the servers remains the only exhaustive verification.
Affected and fixed versions
Google Brotli 1.0.3 to 1.2.0 are affected, fixed in 1.0.10, 1.1.1 and 1.2.1. Fixed releases of the main products embedding it: Node.js 22.23.4, 24.22.1 and 26.12.1 (end-of-life lines 20.x and older and 25.x receive no fix), Bun 1.4.4, Envoy 1.37.8, 1.38.6, 1.39.3 and 1.40.0, Istio 1.29.9, 1.30.6 and 1.31.2, Python Brotli 1.2.1 and brotlicffi 1.2.1.0. Products that link against the system library depend on the Brotli package of the Linux distribution.
Recommendations
Update every component that embeds the Brotli decoder (only real fix). Start with the assets flagged by this control. Restart the processes after the update. Rebuild containers, single-executable applications and appliances that bundle an affected runtime or library.
Reduce the exposure until the update is deployed. Reject requests with "Content-Encoding: br" at the reverse proxy, load balancer or WAF, case-insensitively and including lists such as "gzip, br". On Envoy and Istio, disable request decompression for Brotli.
Review outbound calls. List the features that fetch content from servers you do not control, and patch the services that host them first.
